Backpack frame



FIG. 1 is a front elevation view of the backpack frame.

FIG. 2 is a rear elevation view of the backpack frame.

FIG. 3 is a side plan view of the backpack frame, a side view from the other side would be a similar view mirror image.

FIG. 4 is a top plan view of the backpack frame.

FIG. 5 is a bottom plan view of the backpack frame.

FIG. 6 is a perspective view of the front of the backpack frame; and,

FIG. 7 is a perspective view of the back of the backpack frame. 

The ornamental design for a backpack frame, as shown and described. 